Method for shrinking linewidth of extreme dimension

ABSTRACT

A method for shrinking a linewidth on a substrate includes the steps of applying a stretching force on the substrate, defining a line on a top surface of the substrate and releasing the applied stretching force. The applied force is executed by mechanical stretching or thermal expansion and has a direction parallel to the line.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from application No. 101105376, filed on Feb. 17, 2012 in the Taiwan Intellectual Property Office.

FIELD OF THE INVENTION

The invention relates to a method for shrinking a linewidth, and more particularly, to a method for shrinking a linewidth of extreme scale.

BACKGROUND OF THE INVENTION

Currently, polymer is used as an integral substrate element for carrying electronic devices either on top or at the bottom side of the substrate element. The electronic devices are stacked on the top surface of the substrate element and the technology is mostly used in the semiconductor field. One noted feature of adopting this technology is that the aspect ratio exceeds 10.

One existing technology in record to define a linewidth is that two photoresist layers are applied on the surface of the substrate element. Appropriate control of the exposure energy will define a linewidth in the first photoresist layer while the second photoresist layer is not affected. While the first photoresist layer is defined, the first photoresist layer has an undercut side wall structure. A wet etching is then processed to the second photoresist layer. In the process of wet etching, the undercut structure of the first photoresist layer protects a portion of the second photoresist layer from being etched. Thereafter, a metal evaporation and lift-off is applied to define a linewidth for forming an L-shaped gate.

However, the technology as just described is costly and complex in process. Furthermore, limited by light wavelength, linewidth of smaller scale is not an available.

SUMMARY OF THE INVENTION

One object of the invention is to provide a method for shrinking linewidth of extreme dimension. The method applies a force to a full dimension of the substrate where the line is about to be defined and then an appropriate line defining process is executed on the top surface of the substrate to define lines. After the lines are defined, the applied force is released. Due to stretch to a certain extent as one of the material characteristics as the substrate, when the applied force is released, the recovery force of the substrate shrinks the originally defined linewidth.

The applied force is executed by mechanical stretch or thermal expansion.

Another objective of the present invention is to provide a method for shrinking linewidth of extreme dimension. In this objective, the applied force is exerted on the substrate after the lines are defined.

Still another objective of the present invention is that when the force is applied, Poisson's ratio is maintained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart showing steps involved in the preferred embodiment of the method of this invention;

FIG. 2A is a schematic view showing how the force is applied to the substrate;

FIG. 2B is a schematic view showing the influence caused by the applied force affecting the pattern on the top surface of the substrate;

FIG. 2C is a schematic view showing the releasing of the applied force to the substrate;

FIG. 3 is a flowing chart showing steps involved in yet another preferred embodiment of the present invention;

FIG. 4A is a schematic view showing the first step in the preferred embodiment indicated in FIG. 3; and

FIG. 4B is a schematic view showing the second step in the preferred embodiment indicated in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-2C, it is to be noted that a substrate generally refers to a base made of a soft material such as polymer or glass for carrying thereon semiconductor devices. Within a certain extent, as long as it is in compliance with Poisson's ratio, the substrate normally has stretching and recovering forces when a force is applied to the substrate. That is, the substrate is able to stretch to a certain degree when a force is applied and the substrate tends to return to its original state according to its own recovery force when the additional force is removed.

In the first preferred embodiment 10 of the present invention, the steps involved includes:

step 100, applying a stretching force to a substrate 2 made of a soft material;

step 101, defining a linewidth of a pattern 20 on the top surface of the substrate 2; and

step 102, releasing the stretching force from the substrate.

The stretching force which is applied to the substrate 2 is executed by mechanical force or heat expansion. Two stretching devices 3 are employed to apply the required force to the substrate 2. It is noted that even though the two stretching devices 3 are employed on two opposite sides of the substrate 2 with two opposite forces directing to opposite directions, as shown in FIG. 2A, the applied stretching force should evenly employed to every inch of the substrate 2 so that there will be no stress accumulated in the aftermath process.

When defining the linewidth of a pattern 20 as shown in step 101 and FIG. 2B, a metal electrodeposition process is performed. Preferably, the substrate shape may be elongated, square, trapezoidal, oval or round. In the first embodiment of the present invention, the stretching direction of the applied force is parallel to the linewidth.

After the applied force is removed, the recovery force of the nature of the material for making the substrate will eventually shrink the linewidth of the pattern 20.

With reference to FIGS. 3 to 4B, the second preferred embodiment of the present invention, it is noted that the steps involved in the method include:

step 110: defining a linewidth of a pattern 20 on the top surface of a substrate 2; and

step 111: applying a stretching force to the substrate 2.

The stretching force which is applied to the substrate 2 is executed by mechanical force or heat expansion. Two stretching devices 3 are employed to apply the required force to the substrate 2. It is noted that even though the two stretching devices 3 are employed on two opposite sides of the substrate 2 with two opposite forces directing to opposite directions, the applied stretching force should evenly employed to every inch of the substrate 2 so that there will be no stress accumulated in the aftermath process.

When defining the linewidth of a pattern 20 as shown in step 110, a metal electrodeposition process is performed. Preferably, the substrate shape may be elongated, square, trapezoidal, oval or round. In the first embodiment of the present invention, the stretching direction of the applied force is vertical to the linewidth.

While the invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements. 

What is claimed is:
 1. A method for shrinking a linewidth on a substrate, the method comprising the steps of: applying a stretching force on the substrate; defining a line on a top surface of the substrate; and releasing the applied stretching force.
 2. The method as claimed in claim 1, wherein the line is defined by metal electrodeposition.
 3. The method as claimed in claim 1, wherein the applied force is executed by mechanical stretching or thermal expansion.
 4. The method as claimed in claim 1, wherein a material for the substrate is polymer or glass.
 5. The method as claimed in claim 1, wherein direction of the stretching force is parallel to the line.
 6. A method for shrinking a linewidth on a substrate, the method comprising the steps of: defining a line on the substrate; and applying a stretching force to the substrate.
 7. The method as claimed in claim 6, wherein line is defined by metal electrodeposition.
 8. The method as claimed in claim 6, wherein the stretching force is mechanical force or heat expansion.
 9. The method as claimed in claim 6, a material for the substrate is polymer or glass.
 10. The method as claimed in claim 6, wherein direction of the stretching force is vertical to the line. 